docs: def from_xy(cls, x_array, y_array):
          """ Create a dataset from two arrays of data.
  
              :note: infering the dimensions for the first elements of each array.
          """
          if len(x_array) == 0:
              raise ValueError("data array is empty.")
          dim_x, dim_y = len(x_array[0]), len(y_array[0])
          dataset = cls(dim_x, dim_y)
          for x, y in zip(x_array, y_array):
              assert len(x) == dim_x and len(y) == dim_y
              dataset.add_xy(x, y)
          return dataset